Heating, Air Conditioning, Fridge, HVAC/Return air


Hello I have a split system and the unit downstairs seems to be pulling harder than the return upstairs
Also I have a wood stove and when it cools down in the early hours the unit kicks on and then I have a smoke problem. The unit is on the opposite end of the return grill and the return is a straight shot its 20x24 the unit has a 12x12 grill.

You did not give my anything I need to work from in the question.  The size of the return and a 12 x 12 does not do my any good.  Now, what I can say is that just because it is pulling harder doe not mean it is working harder.  The size of the ducts will determine what the air velocity will be.  Consider the amount of suction power of a vacuum through a 2" hose or a 4" hose.  The amount of air is the same, but the 2" has more suction.  

You need to see if you have a back draft damper on the fireplace and that it works.  You house is going neg. and the smoke is being drawn back inside.


Heating, Air Conditioning, Fridge, HVAC

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Craig HVAC Expert


I have been in the HVAC field for the past 18 years. I can help with most HVAC questions. I work on commerical buildings for the most part, and have yet to find anything I could not troubleshoot and repair, when repairable. I work on small 1 ton units to a 2500 ton chiller. Troubleshoot air flow, elect, and control problems. I attend regular classes to keep up with the latest and greatest.


I work on commerical sites, hospitals, gov't buildings. I can troubleshoot just about anything in the HVAC business.

5 years trade school, VFD training classes, Liebert factory training, some York and Trane factory training.

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